Skip to main content
Workforce LibreTexts

2: Heating

  • Page ID
    18014
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)

    ( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\id}{\mathrm{id}}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\kernel}{\mathrm{null}\,}\)

    \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\)

    \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\)

    \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    \( \newcommand{\vectorA}[1]{\vec{#1}}      % arrow\)

    \( \newcommand{\vectorAt}[1]{\vec{\text{#1}}}      % arrow\)

    \( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vectorC}[1]{\textbf{#1}} \)

    \( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)

    \( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)

    \( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)

    \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)

    • 2.1: Thermostats – General
      This page discusses thermostats, which are devices that manage heating and cooling systems by responding to temperature changes. There are two main types: line-voltage and low-voltage. For optimal performance, thermostat placement away from direct heat sources is essential. Some models include remote sensors tailored for specific settings like in-floor heating or industrial use.
    • 2.2: Line Voltage Thermostats
      This page discusses line-voltage thermostats used for baseboard heaters, highlighting SPST and DPST types. These thermostats serve as efficient on/off switches for individual room heating, ensuring accurate temperature management without affecting adjacent spaces. DPST models feature an "OFF" position, unlike SPST ones. It emphasizes the importance of adhering to proper voltage and wattage ratings for safety and mandates manual disconnection from the power source before servicing heating units.
    • 2.3: Low-Voltage Thermostats
      This page discusses the advantages of low-voltage thermostats for central heating, highlighting their compact size, cost-effectiveness, and sensitivity compared to line-voltage options. They control whole-house temperatures using a transformer and a control relay, ensuring safety and efficiency with a simple two-wire installation. Some models feature anticipator resistors for improved temperature management, and they come in basic or advanced programmable versions.
    • 2.4: Electric Heat – General
      This page discusses electric heating systems for buildings, outlining types like baseboard heaters and central systems. These systems generate heat by passing current through resistive elements, with output varying significantly based on the applied voltage. It highlights that most fixed electric heating loads in homes typically operate at 240V for optimal performance.
    • 2.5: Baseboard Heat
      This page describes baseboard heaters, which are fixed electric units operating at 240V and commonly installed under windows to reduce heat loss. Controlled by line-voltage thermostats, they are available in 250W increments for accurate sizing. Caution is necessary during installation to prevent heat damage to nearby electrical equipment. Some manufacturers provide designs that incorporate receptacles within the heater itself.
    • 2.6: Central Electric Heat
      This page details a central electric furnace, highlighting its components such as resistive heating coils and a blower motor, along with a low-voltage thermostat for control and safety features to prevent overheating. The furnace operates in 5 kW increments, consuming between 5 kW and 40 kW, and can be powered by either single-phase or three-phase voltage depending on installation requirements.
    • 2.7: Unit Heaters
      This page describes unit heaters, compact heating devices typically mounted high or recessed. They include a heating element, blower fan, and directional louvers. For efficiency, airflow should focus on heat-loss areas like windows, and safety measures against overheating are essential. When multiple units are used, airflow should circulate along outer walls. They are controlled by temperature-activated switches and may include an optional fan switch. Capacities vary from 2 kW to 60 kW.
    • 2.8: Portable Heaters
      This page explains that portable electric heaters run on 120V, suitable for various rooms. They usually have built-in thermostats for temperature control and may include fans for effective air distribution.
    • 2.9: In-Floor Heating
      This page describes in-floor heating systems that use resistive heating cables placed beneath floors to improve comfort, particularly in bathrooms, and can also clear snow and ice from outdoor surfaces. The cables, available in mats or rolls, are spaced 150 to 300 mm apart and have power outputs ranging from 40 to 160 watts per square meter. Proper installation is critical to maintain performance, and a thermostat with a remote sensor is used for temperature regulation.
    • 2.10: Gas Heat – Basic Principle
      This page discusses gas-fired furnaces, a popular heating method that converts natural gas into heat, which, although cleaner than other fossil fuels, still produces carbon emissions. These systems can be forced-air or hydronic, utilizing fans or pumps to distribute heat.
    • 2.11: Gas Heat – Control
      This page describes the operation of a central gas heating system, which utilizes a control circuit with a transformer and a separate blower fan circuit. A room thermostat activates the gas valve at low temperatures, heating air through a heat exchanger, while a second thermostat regulates the blower. An anticipator resistor helps prevent temperature overshoot, and a high-temperature cut-out switch ensures safety by shutting off gas if temperatures rise too high.
    • 2.12: Pilot Lights
      This page discusses pilot lights in gas-fired heating systems, explaining their role in igniting gas via a continuous flame and the safety mechanisms involved, such as the thermocouple. It also mentions alternative ignition methods like spark and electronic ignition, which quickly ignite gas when the main valve opens to avoid dangerous gas accumulation.
    • 2.13: Thermocouples
      This page explains how thermocouples, made from two different metals, generate a small voltage when heated, which controls a pilot light safety shut-off gas valve. If the pilot flame goes out, the resulting voltage loss causes the valve to close, preventing gas accumulation. Thermocouples typically produce 25-30 DC millivolts, while thermopiles, made of multiple thermocouples, can generate up to 750 DC millivolts for applications in gas furnaces and thermostats.
    • 2.14: Hydronic Heating Systems
      This page explains hydronic heating systems, which circulate warm water through pipes to heat a room by releasing heat when the room temperature is lower. Continuous water movement enhances heat transfer, requiring an external heating source like a gas or electric boiler. Radiators are strategically placed near windows or heat loss areas for efficient heat distribution.
    • 2.15: Self Test 2
      This page discusses a self-test connected to a book, indicating that the interactive feature is not available in print or digital formats. Users are directed to an online link for access, while quiz questions are included at the end of the book for offline use.

    Thumbnail: Radiator (Unsplash License; Julian Hochgesang via Unsplash)


    This page titled 2: Heating is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by Aaron Lee (BCcampus) via source content that was edited to the style and standards of the LibreTexts platform.